275/60R18 vs 275/65R18 at a glance
| Measure | 275/60R18 (current) | 275/65R18 (new) | Difference |
|---|---|---|---|
| Overall height | 30.99 in | 32.07 in | +1.08 in (+3.49%) |
| Width | 10.83 in (275 mm) | 10.83 in (275 mm) | +0 mm |
| Sidewall | 6.50 in | 7.04 in | +0.54 in |
| Wheel | 18 in | 18 in | +0 in |
| Circumference | 97.4 in | 100.8 in | +3.4 in |
| Revs per mile | 650.7 | 628.8 | −22.0 |
Verdict: check clearance and speedometer
Over 3% and up to 5%: worth checking clearance, the speedometer and gearing before you buy. Going from 275/60R18 to 275/65R18 is a 3.5% increase in overall height (+1.08 in), and the vehicle sits about 0.54 in higher. The tire is the same width. The 3% rule of thumb comes from Discount Tire and 1010tires; it is not a guarantee of fit.
True speed and odometer
| Speedometer shows | You are really doing | Difference |
|---|---|---|
| 35 mph | 36.2 mph | +1.2 mph |
| 45 mph | 46.6 mph | +1.6 mph |
| 55 mph | 56.9 mph | +1.9 mph |
| 60 mph | 62.1 mph | +2.1 mph |
| 65 mph | 67.3 mph | +2.3 mph |
| 70 mph | 72.4 mph | +2.4 mph |
| 75 mph | 77.6 mph | +2.6 mph |
Odometer: 1,000 indicated miles is 1,035 real miles, and 10,000 is 10,349.
The math
275/60R18: 18 + 2 × (275 × 60% ÷ 25.4) = 30.99 in. 275/65R18: 18 + 2 × (275 × 65% ÷ 25.4) = 32.07 in. Change = 32.07 ÷ 30.99 − 1 = +3.49%. True speed at 60 = 60 × 32.07 ÷ 30.99 = 62.10 mph.
Check next
- Regear and RPM at cruise for this swap
- Speedometer and odometer correction
- Other sizes within ±3% of 275/60R18
Calculated from the size alone. Real tires vary a little by brand and model, and the loaded radius is a bit smaller. Confirm the wheel width range, clearance, load index and speed rating for your vehicle. See how to read a tire size, the load index chart and the speed rating chart.
Size pages: 275/60R18 · 275/65R18. More swaps: all tire size comparisons.